Our long-term objective of this research is to establish general rules which govern the mode of assembly of salicylate molecules with other simple molecules representative of biological systems. The salicylates with potent analgesic, antipyretic and anti- inflammatory activities have dual hydrophylic/hydrophobic character which is derived from polar hydroxyl and carboxyl side- chains and a non-polar ring system. By means of single crystal X- ray diffraction we propose to determine the structure of molecular and metal complexes of salicylates with polypeptides, polynucleotides, polynucleotides and lipids. Our aims are to analyze the conformational variation and to study the nature of hydrogen-bounding mode of salicylate derivatives involved in molecular association with other molecules which may be representative of those involved at receptor sites. The results obtained from this research would be useful in understanding the drug action of salicylates.